Field of the Invention
The present invention relates to a plate-integrated gasket which is used in a structure sealing a flow path between a plurality of plates by laminating the plates, for example, a fuel cell, and is structured such that a seal member made of an elastic material having a rubber-like elasticity is integrated in the plate.
Description of the Conventional Art
FIG. 23 shows an example of a gasket for a fuel cell in which a seal member made of an elastic material having a rubber-like elasticity is integrated in a separator of a fuel cell, as a plate-integrated gasket according to a prior art.
In the gasket for the fuel cell, each of reference numerals 101 and 102 denotes a plate-like separator which is made of a conductive material such as a carbon. Among them, on an upper surface of the first separator 101 in an upper side in FIG. 23, a flow path groove 101a, for example, for supplying one of fuel gas (hydrogen gas) and oxidant gas (air) is formed, and a seal member 103 for sealing the gas circulating through the flow path groove 101a is integrally bonded. Further, on a lower surface of the second separator 102 which is laminated in a lower side in FIG. 23, a flow path groove 102a, for example, for supplying the other of the fuel gas (the hydrogen gas) and the oxidant gas (the air) is formed, and a seal member 104 for sealing the gas circulating through the flow path groove 102a is integrally bonded, and on an upper surface of the second separator 102 which is superposed with the lower surface of the first separator 101, a flow path groove 102b, for example, for circulating a fluid such as a cooling water is formed, and a seal member 105 for sealing the fluid circulating through the flow path groove 102b is integrally bonded (refer, for example, to Japanese Unexamined Patent Publication No. 2005-222708).
In other words, this kind of fuel cell gasket is structured such that the seal members 103 to 105 are integrated in the separators 101 and 102 for improving an assembling property, however, it is necessary to separately form the seal member 103 in the separator 101 side and the seal members 104 and 105 in the second separator 102 side, so that a productivity is lower at that degree.
Further, FIGS. 24 and 25 show the other example of the fuel cell gasket in which the seal member made of the elastic material having the rubber-like elasticity is integrated in the separator, as the plate-integrated gasket according to the prior art.
In other words, in the case of the prior art shown in FIG. 24 or 25, the seal member 103 in the first separator 101 side and the seal members 104 and 105 in the second separator 102 side are provided at the positions which are deviated from each other, by making an outer peripheral dimension of the second separator 102 larger than an outer peripheral dimension of the first separator 101, and the seal members 104 and 105 are connected to each other via a communication hole 102c provided in the second separator 102. Accordingly, the seal members 103 to 105 can be formed in the separators 101 and 102 in one forming step by setting the first separator 101 and the second separator 102 in a laminated state to a metal mold 200 which is constructed by an upper mold 201 and a lower mold 202, for example, as shown in FIG. 26. Therefore, a productivity is improved in comparison with the structure in FIG. 23. In this example, the flow path groove 101b for circulating the cooling water is formed in the first separator 101 side.
However, in the case that heights h1 and h2 of the seal member 103 in the separator 101 side and the seal member 105 in the second separator 102 side are different due to existence of the step in the laminating direction between the first separator 101 and the second separator 102 such as an example shown in FIG. 25, it becomes hard to align properties caused by compressibility ratios of the seal members 103 and 105 in an assembled state.
Further, in the prior arts in FIGS. 24 and 25, since seal fixing grooves 101c and 102d for constraining the seal members 103 and 105 in relation to inner and outer peripheral directions are structured such as to be independently provided in the first separator 101 and the second separator 102, as well as the outer peripheral dimension of the second separator 102 is made larger than the outer peripheral dimension of the first separator 101, a width w of an area in which the seal members 103 and 105 are provided becomes larger in comparison with the example in FIG. 23. As a result, a size of a whole of the fuel cell is increased.
Further, as shown in FIG. 26, since the metal mold 200 used for molding needs a plurality of injection ports 203a and 204a for separately filling a molding rubber material into a cavity 203 for molding the seal member 103 in the first separator 101 side, and a cavity 204 for molding the seal members 104 and 105 in the second separator 102 side, there is pointed out such a problem that a structure of the metal mold 200 becomes complicated.